1. Field of the Invention
The present invention relates generally to a voice data gateway (VDG) and, more particularly, to a wireless VDG with telephony and data services functions intended for residential applications.
2. Background Of The Invention
Some business entities have wireless local area network (WLAN) based on the 802.11 technology (including 11b, 11a, and 11g) that utilizes the same air interface as 802.11b-based cordless telephones. The 802.11b-based cordless telephones, however, are typically intended for enterprise applications where the 802.11b handset communicates over an existing office LAN to an IP based softswitch to support VoIP communication either over dedicated data trunks to remote locations or to a PSTN connection via an IP-to-PSTN gateway.
Such 802.11b telephony system is costly, and it is not intended for residential applications. Furthermore, the existing 802.11b systems support voice/data with limited range and talk/standby time not suitable for residential applications.
Although some cellular or mobile telephone handsets (in non-802.11b applications) are equipped to handle data and are Internet enabled, these handsets deliver limited content over a relatively low-speed data link supported through the cellular network.
It is quite rare to find a residential unit that employs an integrated wireless voice/data system such as a home RF voice/data gateway. Many homes today are equipped with a cordless telephone, a wireless and/or wired data network, and a broadband connection to the outside world. The telephone, data network, and broadband connection, however, are not interoperable.
FIG. 1 shows a conventional system that uses external IP-to-PSTN gateway 100 to convert analog signals received from the PSTN network and sends packetized signals via Ethernet local area network (LAN) 101 and WLAN access point 102 to cordless handset 103. The transmission uses 802.11 standard data rates that are not optimized for power consumption. A typical application requires the user to configure IP-to-PSTN gateway 100 to communicate with WLAN access point 102 via a proprietary protocol. This protocol needs to synchronize the voice CODECs used by the 802.11-based handset 103 and IP-to-PSTN gateway 100. In addition, both IP-to-PSTN gateway 100 and WLAN access point 102 have to agree on a number of items, including, for example, how to communicate to handset 103 and PSTN network signaling commands (such as DTMF tones, VMWI tones, ring signals, CID message decoding, etc.). The typical system of FIG. 1 has the disadvantage of using an external IP-to-PSTN gateway, using a private network infrastructure for communicating with the WLAN access point, and utilizing a complicated set of rules and protocols for communicating signaling information to the WLAN access point. Furthermore, this convention system has limited cordless range and poor talk/standby time performance.
FIG. 2 shows a convention system that uses a central-office-located IP based softswitch 200. Softswitch 200 converts packetized voice signals that were originated at 802.11 cordless handset 203 and arrive at softswitch 200 via broadband network 201 and wireless access point 202. A typical application of this system requires the broadband service provider to set up the softswitch on their premises, set up a broadband network that support voice services, and specify the protocol to communicate signaling and voice information between the softswitch, the access point and the 802.11 handset. Furthermore, this system has limited cordless range and poor talk/standby time performance.
FIG. 3 shows a conventional cordless system that is used to provide access to the PSTN network from cordless handset 302 via cordless base 301. FIG. 4 shows a conventional 802.11 based data network, in which access point 402 provides broadband access to wireless terminal 403 and wired terminal 404 via external modem 401.
Each of the known systems described above has disadvantages and limitations. Accordingly, there is a need for a system that has the functionality to combine the flexibility to support both conventional PSTN telephony and broadband telephony. There is also a need for a system that provides the ability to deliver data content to a cordless handset without the need of external equipment. In addition, the system should preferably be able to support other enhanced telephony functions (such as voice recognition and voice synthesis) by utilizing the interconnection to wired data terminal (e.g., a personal computer) and the associated computer processing power.